Blow molded boxes of double wall construction (i.e., having walls formed by inner and outer polymeric sheets spaced apart along most of their adjacent portions and connected together in spaced locations and along many of their edges) are widely used where economy, durability and light weight are desired. The light weight reduces shipping costs and the double wall construction provides cushioning against shocks.
One such two part blow molded box available from Minnesota Mining and Manufacturing Company, St. Paul, Minn., has been particularly adapted to protect videocassettes and has been constructed with a special hinge between the parts, a special double acting latch, and a recessed hook for hanging the boxes from a horizontal support member as is described respectively in U.S. Pat. Nos. 4,211,337: 4,153,178 and 4,177,896, the content whereof is incorporated herein by reference. While that box has achieved great acceptance, experience with the box in the field has shown a need to provide certain improvements.
Such boxes containing videocassettes undergo rough handling including being dropped or thrown, which has resulted in crushing in the outer polymeric sheet forming the walls at a corner of the box. Such corner crushing is not only unsightly, but can also cause torsional forces in and deform the box part on which the crushed corner is formed so that it will no longer properly engage a mating part to close the box.
More dust than may be desired has found its way into the closed boxes, particularly through the hinge portions.
Also, it has been found difficult to carry a large stack of the boxes due to slippage between the relatively slippery and generally planar side surfaces of the boxes.